Distribution of extra- and intrathoracic pressure variations in rabbits exposed to air shock waves.

Abstract

AbstractRabbits were exposed directly, and excised rabbit and calf lungs after mounting in a pulse guide system, to high explosive air shock waves in a detonation chamber. The incident shock wave as well as the resulting pressure wave patterns were recorded by means of piezoelectric pressure transducers, simultaneously in the lungs, in the heart ventricles, or in the intercostal musculature of both sides of the thorax in the in vivo experiments, and immediately before and after the passage of the lung in the experiments in the pulse guide system. The velocity of propagation of the main part of a pressure pulse in the lung generally was found to be of the order of 15 to 30 m/sec. The velocity of the same type of pulse through the whole chest of some guinea pigs exposed in the pulse guide was of the same order of magnitude, indicating that the main part of the pulse in this case was transmitted through the lungs and not in the thoracic wall structures, which have a much higher transmission velocity. The very low intrathoracic transmission velocity indicates that in an animal, which is exposed freely to and engulfed by the shock wave, the main resulting pressure wave is not propagated through the thorax from one lung to the other. In this case a very complex relationship exists between the temporal and spatial distribution of the resulting extra‐ and intrathoracic forces.